It is known for vehicle heating, cooling and air conditioning systems to use the waste heat of the engine exhaust as part of an absorption system in order to provide dehumidified warm or cold air to the interior of the vehicle. One such system is disclosed in U.S. Pat. No. 5,383,341, which discloses an absorption system in which a refrigerant-absorbent mixture is heated by the exhaust gases from the engine of the vehicle. The refrigerant-absorbent mixture is contained within a reactor vessel, and the mixture may comprise a sodium thiocyanate (NaSCN) salt acting as the absorbent and an ammonia (NH3) solution acting as the refrigerant. The reactor vessel is heated by heat extracted from the engine exhaust gases which pass through an exhaust pipe.
The reactor vessel is remote from the exhaust pipe, with the heat from the exhaust gases transferred to the reactor by a plurality of heat pipes. Each heat pipe has an evaporator section which lies within the exhaust pipe and a condenser section which lies within the reactor vessel. The exhaust gases flow over and heat the evaporator sections of the heat pipes, which causes a volatile medium contained within each heat pipe to vaporise and flow towards the condenser section. The vapour condenses back into a liquid within the condenser sections of each pipe, thereby distributing the heat output into the refrigerant-absorbent mixture within the reactor vessel.
It is an aim of the present invention to provide an improved exhaust gas-driven absorption system for heating, cooling and conditioning air for the operator cab or driver/passenger environment of a vehicle.